Crate mnem_transport 

mnem-transport

Offline transport for mnem: export a subtree of the content-addressed DAG to a CAR v1 archive, ship it anywhere (USB stick, email, scp, S3), import on the other side.

CAR (Content-Addressable aRchive) is IPFS’s standard bundling format: a stream of (varint length, CID, bytes) triples preceded by a varint-framed DAG-CBOR header that lists the root CIDs. It is streamable in both directions; this crate implements the CAR v1 wire shape exactly.

Shape

• export walks the Blockstore from a root CID via the Blockstore::iter_from_root default impl, writing every reachable block to a std::io::Write.
• import reads a CAR from a std::io::Read and inserts every block into a target blockstore, verifying the CID on each block.
• car exposes the lower-level CAR reader / writer used by the above, for callers that need to interleave CAR parsing with other work.

In addition to the file-format half, this crate is home to the shapes of mnem’s remote wire protocol:

• protocol freezes the protocol::PROTOCOL_VERSION integer, the protocol::PROTOCOL_HEADER HTTP header name, and the protocol::Capability vocabulary. PR 2 does not ship any wire code; it ships the agreement surface so PR 3 can add verbs without a version bump.
• remote defines remote::RemoteConfig, the in-memory type parsed from the [remote.<name>] section of .mnem/config.toml.
• have_set defines the have_set::HaveSet trait and the have_set::BloomHaveSet reference back-end used to summarise “blocks I already have” on fetch- blocks / push-blocks.

Everything in those three modules is pure data + pure functions. HTTP wiring lives in mnem http; the CLI glue (mnem remote add etc.) lives in mnem-cli; neither lands until PR 3.

Constraints

• WASM-clean. No tokio, no async. The entire interface is std::io::{Read, Write} with ?Sized support.
• No filesystem helpers; callers open files and pass the handles. Keeps this crate usable inside HTTP streams, pipes, etc.
• Deterministic ordering: export writes blocks in iter_from_root’s depth-first order so the same root produces a byte-identical CAR across runs.

Re-exports

pub use error::ClientError;

pub use error::TransportError;

pub use export::ExportStats;

pub use export::export;

pub use have_set::BloomHaveSet;

pub use have_set::HaveSet;

pub use have_set::build_have_set;

pub use import::ImportStats;

pub use import::import;

pub use protocol::CAPABILITIES_HEADER;

pub use protocol::Capability;

pub use protocol::CapabilitySet;

pub use protocol::PROTOCOL_HEADER;

pub use protocol::PROTOCOL_VERSION;

pub use protocol::parse_capabilities;

pub use protocol::serialize_capabilities;

pub use remote::RemoteConfig;

pub use remote::RemoteConfigFile;

pub use remote::RemoteSection;

pub use remote::parse_config;

pub use secret_token::SecretToken;

pub use client::HttpRemoteClient;

pub use client::PushResponse;

pub use client::RefsResponse;

pub use client::RemoteClient;

Modules

car

CAR v1 reader + writer.

client

Async HTTP RemoteClient.

error

Transport-layer error type.

export

Export a reachable subtree of a Blockstore to CAR v1.

have_set

HaveSet trait and the PR-2 BloomHaveSet reference implementation.

import

Import a CAR v1 archive into a Blockstore.

protocol

Wire-level protocol constants and capability vocabulary for mnem’s remote transport.

remote

RemoteConfig and the .mnem/config.toml [remote.<name>] schema.

secret_token

Opaque bearer-token newtype used by the remote transport.

Constants

VERSION

Library version (tracks the workspace package version).